Printer

A thermal transfer printer comprising:

• first and second spool supports each being configured to support a spool of ink carrying ribbon;
• a ribbon drive configured to cause movement of ribbon from the first spool support to the second spool support;
• and
• a printhead configured to be selectively energised so as cause ink to be transferred from the ribbon to the substrate so as to cause a mark to be created on the substrate;
• the ribbon drive comprising:
• a stepper motor having an output shaft operably associated with one of said spool supports, the stepper motor being arranged to cause said one of the spool supports to rotate to cause said movement of ribbon from the first spool support to the second spool support;
• a sensor configured to generate a signal indicative of an angular position of the output shaft of the stepper motor;
• and
• a controller arranged to generate control signals for the stepper motor;
• said control signals being at least partially based upon an output of said sensor and at least partially based upon a target position wherein:
• said control signals for the stepper motor are arranged to cause a magnetic field to be generated by windings of the stepper motor, a field angle being defined between an angular position of the output shaft of the stepper motor, and an orientation of the generated magnetic field;
• said control signals comprise a first control signal configured to cause said field angle to have a predetermined value, and a second control signal configured to cause said magnetic field to have a predetermined magnitude;
• and
• said controller is configured to vary said first and second control signals based upon said target position and said output of said sensor.